Conflicting feelings.

Recently I (21F) broke up with my boyfriend (22M) for context it was due to quite a few incidents that showed me that his insecurities were too much for me to help with, one of the points I brought up at the time was that I felt like he didn’t know who he was as a person, we dated for 2 years and we started dating a few months after he broke up with 5 years long relationship.

Anyway skip to the present. It’s been a month or two since we ended things and I run across his exes acc on my recommended and I clicked on it to see they were both following each other again and I don’t know why it’s just making me feel a bit upset. And I can’t really say anything cause it’s obviously none of my business anymore and I had a thing with a random guy a few weeks after the breakup which is worse but it’s still bugging me for some reason.

Is this normal? Or am I sounding out of my lane? I obviously won’t be saying anything to him this is more for peace of mind.